effective microorganism (s) (EM) / (EM Technology)

A trademarked term now commonly used to describe a proprietary blend of 3 or more types of predominantly anaerobic organisms that was originally marketed as EM-1 Microbial Inoculant but is now marketed by a plethora of companies under various names, each with their own proprietary blend. "EM Technology" uses a laboratory cultured mixture of microorganisms consisting mainly of lactic acid bacteria, purple bacteria, and yeast which co-exist for the benefit of whichever environment they are introduced, as has been claimed by the various em-like culture purveyors. Source: Wikipedia